fix test + add new case

Signed-off-by: Victor Garcia Reolid <victor@seita.nl>

flexmeasures/data/models/planning/tests/conftest.py

@@ -223,13 +223,17 @@ def process(db, building, setup_sources) -> dict[str, Sensor]:
 def add_stock_gain(db, add_battery_assets, setup_sources) -> dict[str, Sensor]:
     """
     Set up the same constant gain (-capacity_in_mw) in different resolutions.
+
+    In 15 min event resolution, the maximum energy that the battery can produce/consume in period
+    is 0.25 * capacity_in_mw
     """
 
     battery = add_battery_assets["Test battery"]
     capacity = battery.get_attribute("capacity_in_mw")
     sensors = {}
     sensor_specs = [
-        ("gain", timedelta(minutes=15), capacity, True),
+        ("gain fails", timedelta(minutes=15), capacity, True),
+        ("gain", timedelta(minutes=15), capacity * 0.25, True),
         ("gain hourly", timedelta(hours=1), capacity, True),
         ("gain None", timedelta(hours=1), -capacity, None),
         ("gain consumption is negative", timedelta(hours=1), -capacity, False),

flexmeasures/data/models/planning/tests/test_solver.py

@@ -1452,7 +1452,7 @@ def test_battery_power_capacity_as_sensor(
 
 @pytest.mark.parametrize(
     "stock_gain_sensor",
-    ["gain", "gain hourly", "gain None", "gain consumption is negative"],
+    ["gain fails", "gain", "gain hourly", "gain None", "gain consumption is negative"],
 )
 def test_battery_stock_gain_sensor(
     add_battery_assets, add_stock_gain, stock_gain_sensor
@@ -1489,13 +1489,13 @@ def test_battery_stock_gain_sensor(
             "soc-at-start": 0,
         },
     )
-    stock_gain_constraint = scheduler._prepare()[5][0]["stock gain"]
 
-    assert all(stock_gain_constraint == -capacity)
-
-    schedule = scheduler.compute()
-
-    assert all(schedule == capacity)
+    if "fails" in stock_gain_sensor:
+        with pytest.raises(InfeasibleProblemException):
+            schedule = scheduler.compute()
+    else:
+        schedule = scheduler.compute()
+        assert all(schedule == capacity)
 
 
 @pytest.mark.parametrize(